Mandzukic is Croatia's main striker and will line up against the Three Lions in Moscow aiming to fire his country into Sunday's final.
The Juventus forward is anticipating a tight last-four clash and believes both teams fully deserve their place in the semi and admits he always fancied Gareth Southgate's side to go far in Russia.
He said: "England was one of the favourites for me before the tournament because they have a young, hungry team with no international movie stars.
"We know every England player, respect them as a team and individuals. It's a 50:50 chance. England deserve to be here. We deserve to be here."
Croatia are aiming to make their first ever World Cup final and are into the last four for the first time since 1998, when they lost 2-1 to eventual winners France, while this is England's first semi on the world stage since the penalty shoot-out defeat to West Germany in 1990.